HowTo/Migrate your code to the new LDAP API

A new LDAP API has been introduced to the framework in FreeIPA 3.2 (see V3/LDAP code). Compatibility with the old legacy API has been kept in place but is currently in the process of being deprecated. Any attempt to use the old API will cause an exception to be raised in FreeIPA 4.0. The old API will be completely removed in FreeIPA 4.1.